1. Field of the Invention
This invention relates to a substrate processing apparatus and a method for manufacturing a semiconductor device,
2. Description of the Related Art
In an individual substrate type substrate processing apparatus, a substrate is typically processed in a state in which the substrate is forcefully adsorbed onto a susceptor. In this case, if a degree of contact of the substrate with the susceptor remains uncontrolled, there is a problem that the substrate with a bad degree of contact will have a remarkably deteriorated substrate property when moving to a subsequent film formation step.
In the individual substrate type substrate processing apparatus, as shown in FIG. 3, in a state in which a substrate 1 is adsorbed and supported onto a susceptor 2 which is heated by a resistance heating heater 3, a gas is blown like a shower on the substrate 1 from a gas dispersion plate 5 which is located above the substrate 1, and consequently, a processing such as a film formation and the like will be performed on the substrate 1. A surface of the resistance heating heater 3 heats the susceptor 2 such that a temperature of the susceptor 2 is always maintained at a constant temperature.
Here, when warpage amounts d1 and d2 representing a degree of contact change which are space distances from the substrate 1 to the susceptor 2, a heat of the susceptor 2 which is always uniformly heated in an unchanging state by the resistance heating heater 3 can not be equally transferred to the substrate 1. As a result, a malfunction occurs a the substrate surface, as will be described below, due to temperature distribution nonuniformity depending on the above-noted substrate warpage amount d (a generic name for dl an d2)
Here, a warpage amount of a substrate refers to a maximum value of a gap formed between the susceptor 2 surface and the substrate 1 underside due to an uncontacted portion of the substrate 1 with the susceptor 2 occurring as a result of a deformation of the substrate 1 In a state in which the substrate 1 is supported onto the surface the susecptor 2.
The longer the distance d between the substrate 1 and the susceptor 2 is, the worse thermal conductivity from the susceptor 2 is. Accordingly, the temperature in the substrate surface will have thermal variations generated depending on the distance d. As a result, in the case of d1 greater than d2, the substrate temperature near d2 is higher than the substrate temperature near d1.
In a technique with regard to such a warpage of a substrate, there are conventionally known examples as follows.
(a) Japanese Patent Application Laid-Open No. 7-316811
Since occurrence of a large difference in a temperature distribution in a wafer generates a warpage in the wafer which leads to a cause for occurrence of a slip and the like, an attempt has been made to realize uniformity in the temperature in the wafer surface when being in a steady state or in a transient state (when raising a temperature) by allowing a heating state of a division type heater to be variable based on temperature differences between respective zones in the wafer each temperature of which is measured with a thermocouple.
In addition, heating of the temperature difference in the surface of the wafer, mentioned here, is controlled such that the temperature difference is equal to 10xc2x0 C. or less based on a maximum temperature difference 10xc2x0 C. wherein no warpage occurs at a processing temperature of 300xc2x0 C. That is, the temperature difference value is controlled by one fixed temperature difference in the surface.
(b) Japanese Patent Application Laid-Open No. 6-260426
Since a contact area between a wafer and a susceptor changes due to deformation of the wafer when raising a temperature, the change will affect an outermost circumferential temperature of the wafer so that a temperature difference in the surface occurs to generate a slip.
Therefore, temperature measuring points and a heating method are disclosed in order to inhibit the slip from occurring. That is, by measuring temperatures at a plurality of points of a circumferential portion of the wafer at a distance equal to 70% or more of a radius of the wafer from a center of it, and by controlling heating of a heater such that a temperature difference between the temperature measuring points is within 5xc2x0 C. (this value is a value wherein no slip occurs at 800xc2x0 C. or more), a heating processing without occurrence of a slip is performed without depending uniformity in a heat density of the heater and without depending a contact area between the wafer and the susceptor.
However, in the above-described prior art, there have been problems as follows.
(1) In the known example (a), a temperature rise is controlled by one value of a temperature difference xcex94t in the surface (a value wherein no warpage occurs at a processing temperature (at a setpoint temperature when raising a temperature)). Since this makes it required that the heating be severely controlled when being at a low wafer temperature with a large margin of a xcex94t, by using a xcex94t when being at a high temperature (the xcex94t when being at a low wafer temperature is larger than the xcex94t when being at a high wafer temperature), restriction on a control response is required so as to make a sacrifice of a temperature rising speed. As a result, since the xcex94t margin becomes also small when being at a low temperature, a warpage can be inhibited, however, it can not be ensured that the temperature rising speed is increased.
(2) In the known example (b) which is similar to the known example (a), since heating is controlled by one value (a temperature difference in the surface), there is also a defect similar to the one in the known example (a).
An object of the present invention is to provide a method for processing a substrate and a method for manufacturing a semiconductor device wherewith, by resolving the problems with the prior art noted in the foregoing, occurrence of a warpage of a substrate can be effectively prevented.
A first invention is a substrate processing apparatus which heats a substrate using a heating member capable of performing an unequal heating in a substrate surface, comprising a controller, the controller being adapted to obtain in accordance with a heating state of the substrate such a temperature deviation xcex94t in the substrate surface, which varies in accordance with the heating state of the substrate, that no warpage of the substrate occurs, and the controller being adapted to control the heating member such that a temperature deviation in the surface of the substrate which is heated by the heating member is maintained within the xcex94t. Since heating of the substrate can be controlled based on the temperature deviation xcex94t in the substrate surface, occurrence of a warpage of the substrate can be effectively prevented. Moreover, since the temperature deviation xcex94t in the substrate surface is allowed not to be fixed but to be variable, heating need not be severely controlled when the substrate is at a low temperature with a large margin of a xcex94t, by using a xcex94t value when being at a high temperature. Accordingly, since the heating is controlled with a large xcex94t margin when being at a low temperature, it can be ensured that the temperature rising speed is increased while a warpage can be inhibited at the same time. The above-noted heating member capable of performing an unequal heating in the substrate surface is, for example, a division type heater which is divided into a plurality of zones.
A second invention is a substrate processing apparatus which heats a substrate using a heating member capable of performing an unequal heating in a substrate surface, comprising a controller, the controller being adapted to obtain a xcex94t, which varies in accordance with a temperature when heating, for each of a plurality of temperatures which are selected from the temperatures when heating, the temperature when heating being a temperature of the substrate or a temperature of a substrate support member for supporting the substrate, the xcex94t being such a temperature deviation in the substrate surface that no warpage of the substrate occurs, and the controller being adapted to control the heating member such that a temperature deviation in the surface of the substrate which is heated by the heating member is maintained within the xcex94t based on the temperature of the substrate support member or the substrate temperature at that time. Since there is a correlation between the substrate temperature and the substrate support member temperature, the temperature deviation xcex94t in the substrate surface may be obtained from either of the temperatures. In either event, since the control is performed by the temperature deviation xcex94t in the substrate surface, which varies in accordance with the temperature of the substrate support member or the substrate when heating, that can be easily measured, it can be ensured that the temperature rising speed is increased while a warpage of the substrate can be prevented at the same time.
A third invention is a substrate processing apparatus according to the second invention, wherein the temperature deviation xcex94t in the substrate surface which is obtained in accordance with the temperature of the substrate when heating, is represented by the following expression:
xcex94txe2x89xa6350xc3x97EXP(xe2x88x920.004xc3x97T), 
wherein T is the temperature of the substrate.
Since heating of the substrate is controlled by the temperature deviation xcex94t in the substrate surface represented by the above expression, a warpage of the substrate can be prevented effectively over the whole temperature of the substrate.
A fourth invention is a substrate processing apparatus according to the third invention, wherein a size of the substrate is 12 inches, the xcex94t is a temperature deviation in a surface between a center of the substrate and a position of 145 mm from the substrate center. For the substrate size of 12 inches, if the temperature deviation in the surface between the center of the substrate and the position of 145 mm from the substrate center is obtained, it can be ensured that heating control of the substrate is optimized when performing the control of the heating member.
A fifth invention is a substrate processing apparatus according to the second invention, wherein the temperature deviation xcex94t in the substrate surface is obtained in accordance with a temperature of the substrate support member for supporting the substrate. Since the temperature deviation xcex94t in the substrate surface is obtained by measuring not the substrate temperature but the substrate support member temperature, it is possible to make a thermometer impervious to a substrate processing as compared with a case in which the substrate temperature susceptible to the substrate processing is measured, so that reliability of control is increased.
A sixth invention is a substrate processing apparatus according to the fifth invention, wherein as the temperature of the substrate support member, a temperature of a back surface of the substrate support member opposite to a surface which supports the substrate is measured. Since there is no need to expose a thermometer to a processing space owing to the measurement of the back surface temperature of the substrate support member, an unnecessary film and the like can be prevented from being deposited on the thermometer so that the reliability is further increased.
A seventh invention is a substrate processing apparatus according to the first invention or the second invention, wherein the control of the heating member is a control during a temperature raising process of the substrate. Since a warpage of the substrate, which is not eliminated when processing the substrate, due to variations of the temperature in the substrate surface which have a possibility of occurrence during a temperature raising process, can be surely eliminated, defective processing of the substrate caused by the temperature nonuniformity due to the warpage of the substrate can be reduced.
An eighth invention is a substrate processing apparatus, which heats a substrata using a heating member capable of performing an unequal heating in a substrate surface, and which controls heating of the substrate at least between a first temperature and a second temperature which is different from the first temperature, the substrate processing apparatus comprising a controller, the controller controlling the heating of the substrate such that a temperature deviation in the substrate surface is maintained within a range of such a temperature deviation in the substrate surface that no warpage of the substrate occurs, and wherein a temperature deviation value in the substrate surface at the first temperature and a temperature deviation value in the substrate surface at the second temperature are set to be different, and the heating of the substrate is controlled by using these temperature deviation values which are different values from each other. Since heating of the substrate is controlled based on at least two different temperature deviations in the substrate surface, occurrence of a warpage of a substrate can be prevented with a sufficient control margin as compared with a substrate processing apparatus for controlling heating of a substrate based on one fixed temperature deviation in a substrate surface.
A nineth invention is a substrate processing apparatus according to the eighth invention, wherein the second temperature is a temperature higher than the first temperature, the temperature deviation value in the substrate surface at the first temperature is a value larger than that of the temperature deviation value in the substrate surface at the second temperature, and the heating of the substrate is controlled by using these temperature deviation values which are different values from each other. Since the temperature deviation value in the substrate surface at the first temperature is allowed to be a value larger than that of the temperature deviation value in the substrate surface at the second temperature, a further sufficient margin can be secured during a temperature raising process in which the substrate temperature becomes the first temperature.
A tenth invention is a method for manufacturing a semiconductor device, which heats a substrate using a heating member capable of performing an unequal heating in a substrate surface, the method being adapted to control heating of the substrate by: obtaining in accordance with a heating state of the substrate such a temperature deviation xcex94t in the substrate surface, which varies in accordance with the heating state of the substrate, that no warpage of the substrate occurs; and controlling the heating member such that a temperature deviation in the surface of the substrate which is heated by the heating member is maintained within the xcex94t. Since heating of the substrate is controlled based on the temperature deviation xcex94t in the substrate surface, occurrence of a warpage of the substrate can be effectively prevented. In addition, since the temperature deviation xcex94t in the substrate surface is allowed not to be fixed but to be variable, heating need not be severely controlled when the substrate is at a low temperature with a large margin of a xcex94t, by using a xcex94t value when being at a high temperature. Accordingly, since the xcex94t margin is large when being at a low temperature, it can be ensured that the temperature rising speed is increased while a warpage can be inhibited.
An eleventh invention is a method for manufacturing a semiconductor device, which heats a substrate using a heating member capable of performing an unequal heating in a substrate surface, the method being adapted to control heating of the substrate by: obtaining a xcex94t, which varies in accordance with a temperature when heating, for each of a plurality of temperatures which are selected from the temperatures when heating, the temperature when heating being a temperature of the substrate or a temperature of a substrate support member for supporting the substrate, the xcex94t being such a temperature deviation in the substrate surface that no warpage of the substrate occurs; and controlling the heating member such that a temperature deviation in the surface of the substrate which is heated by the heating member is maintained within the xcex94t based on the temperature of the substrate support member or the temperature of the substrate at that time. Since there is a correlation between the substrate temperature and the substrate support member temperature, the temperature deviation xcex94t in the substrate surface may be obtained by either of the temperatures. In either event, since the control is performed within the temperature deviation xcex94t in the substrate surface which varies in accordance with the temperature of the substrate support member or the substrate when heating, that can be easily measured, it can be ensured that the temperature rising speed is increased while a warpage of the substrate can be inhibited.
A twelfth invention is a method for manufacturing a semiconductor device, which heats a substrate using a heating member capable of performing an unequal heating in a substrate surface, and controls heating of the substrate at least between a first temperature and a second temperature which is different from the first temperature, the method comprising: controlling heating of the substrate such that a temperature deviation in a surface of the substrate is maintained within a range of such a temperature deviation in the substrate surface that no warpage of the substrate occurs; and setting a temperature deviation value in the substrate surface at the first temperature and a temperature deviation value in the substrate surface at the second temperature to be different, and controlling the heating of the substrate by using these temperature deviation values which are different values from each other. Since heating of the substrate is controlled based on at least two different temperature deviations in the substrate surface, occurrence of a warpage of a substrate can be prevented with a sufficient control margin as compared with a method for controlling heating of a substrate based on one fixed temperature deviation in a substrate surface.